Publications by authors named "Eleonora Aronica"

368 Publications

Evolution of electroencephalogram in infants with tuberous sclerosis complex and neurodevelopmental outcome: a prospective cohort study.

Dev Med Child Neurol 2021 Oct 2. Epub 2021 Oct 2.

Department of Development and Regeneration, Section Pediatric Neurology, Catholic University of Leuven (KU Leuven), Leuven, Belgium.

Aim: To describe the evolution of electroencephalogram (EEG) characteristics in infants with tuberous sclerosis complex (TSC) and the relationship with neurodevelopmental outcome at 24 months.

Method: Eighty-three infants were enrolled in the EPISTOP trial and underwent serial EEG follow-up until the age of 24 months (males n=45, females n=37, median age at enrolment 28d, interquartile range 14-54d). Maturation of the EEG background and epileptiform discharges were compared between the TSC1 and TSC2 variants and between preventive and conventional groups respectively.

Results: Children with TSC2 more frequently had a slower posterior dominant rhythm (PDR) at 24 months (51% vs 11%, p=0.002), a higher number of epileptiform foci (median=8 vs 4, p=0.003), and a lower fraction of EEGs without epileptiform discharges (18% vs 61%, p=0.001) at follow-up. A slower PDR at 24 months was significantly associated with lower cognitive (median=70 vs 80, p=0.028) and motor developmental quotients (median=70 vs 79, p=0.008). A higher fraction of EEGs without epileptiform discharges was associated with a lower probability of autism spectrum disorder symptoms (odds ratio=0.092, 95% confidence interval=0.009-0.912, p=0.042) and higher cognitive (p=0.004), language (p=0.002), and motor (p=0.001) developmental quotients at 24 months.

Interpretation: TSC2 is associated with more abnormal EEG characteristics compared to TSC1, which are predictive for neurodevelopmental outcome.
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http://dx.doi.org/10.1111/dmcn.15073DOI Listing
October 2021

ApoE4 disrupts interaction of sortilin with fatty acid-binding protein 7 essential to promote lipid signaling.

J Cell Sci 2021 Oct 21;134(20). Epub 2021 Oct 21.

Max-Delbrueck-Center for Molecular Medicine, 13125 Berlin, Germany.

Sortilin is a neuronal receptor for apolipoprotein E (apoE). Sortilin-dependent uptake of lipidated apoE promotes conversion of polyunsaturated fatty acids (PUFA) into neuromodulators that induce anti-inflammatory gene expression in the brain. This neuroprotective pathway works with the apoE3 variant but is lost with the apoE4 variant, the main risk factor for Alzheimer's disease (AD). Here, we elucidated steps in cellular handling of lipids through sortilin, and why they are disrupted by apoE4. Combining unbiased proteome screens with analyses in mouse models, we uncover interaction of sortilin with fatty acid-binding protein 7 (FABP7), the intracellular carrier for PUFA in the brain. In the presence of apoE3, sortilin promotes functional expression of FABP7 and its ability to elicit lipid-dependent gene transcription. By contrast, apoE4 binding blocks sortilin-mediated sorting, causing catabolism of FABP7 and impairing lipid signaling. Reduced FABP7 levels in the brain of AD patients expressing apoE4 substantiate the relevance of these interactions for neuronal lipid homeostasis. Taken together, we document interaction of sortilin with mediators of extracellular and intracellular lipid transport that provides a mechanistic explanation for loss of a neuroprotective lipid metabolism in AD.
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http://dx.doi.org/10.1242/jcs.258894DOI Listing
October 2021

Interactome screening of C9orf72 dipeptide repeats reveals VCP sequestration and functional impairment by polyGA.

Brain 2021 Sep 17. Epub 2021 Sep 17.

Department of Biotechnology, Jožef Stefan Institute, Ljubljana, Slovenia.

Repeat expansions in the C9orf72 gene are a common cause of amyotrophic lateral sclerosis and frontotemporal lobar degeneration, two devastating neurodegenerative disorders. One of the proposed mechanisms of GGGGCC repeat expansion is their translation into non-canonical dipeptide repeats, which can then accumulate as aggregates and contribute to these pathologies. There are five different dipeptide repeat proteins (polyGA, polyGR, polyPR, polyPA and polyGP), some of which are known to be neurotoxic. In the present study, we used BioID2 proximity labelling to identify the interactomes of all five dipeptide repeat proteins consisting of 125 repeats each. We identified 113 interacting partners for polyGR, 90 for polyGA, 106 for polyPR, 25 for polyPA, and 27 for polyGP. Gene Ontology enrichment analysis of the proteomic data revealed that these target interaction partners are involved in a variety of functions, including protein translation, signal transduction pathways, protein catabolic processes, amide metabolic processes, and RNA-binding. Using autopsy brain tissue from patients with C9orf72 expansion complemented with cell culture analysis, we evaluated the interactions between polyGA and valosin-containing protein (VCP). Functional analysis of this interaction revealed sequestration of VCP with polyGA aggregates, altering levels of soluble VCP protein. VCP also functions in autophagy processes, and consistent with this, we observed altered autophagy in cells expressing polyGA. We also observed altered co-localisation of polyGA aggregates and p62 in cells depleted of the VCP protein. Altogether these data suggest that sequestration of VCP with polyGA aggregates contributes to the loss of VCP function, and consequently to alterations in autophagy processes in C9orf72 expansion disorders.
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http://dx.doi.org/10.1093/brain/awab300DOI Listing
September 2021

CXCL1-CXCR1/2 signaling is induced in human temporal lobe epilepsy and contributes to seizures in a murine model of acquired epilepsy.

Neurobiol Dis 2021 10 4;158:105468. Epub 2021 Aug 4.

Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Italy. Electronic address:

CXCL1, a functional murine orthologue of the human chemokine CXCL8 (IL-8), and its CXCR1 and CXCR2 receptors were investigated in a murine model of acquired epilepsy developing following status epilepticus (SE) induced by intra-amygdala kainate. CXCL8 and its receptors were also studied in human temporal lobe epilepsy (TLE). The functional involvement of the chemokine in seizure generation and neuronal cell loss was assessed in mice using reparixin (formerly referred to as repertaxin), a non-competitive allosteric inhibitor of CXCR1/2 receptors. We found a significant increase in hippocampal CXCL1 level within 24 h of SE onset that lasted for at least 1 week. No changes were measured in blood. In analogy with human TLE, immunohistochemistry in epileptic mice showed that CXCL1 and its two receptors were increased in hippocampal neuronal cells. Additional expression of these molecules was found in glia in human TLE. Mice were treated with reparixin or vehicle during SE and for additional 6 days thereafter, using subcutaneous osmotic minipumps. Drug-treated mice showed a faster SE decay, a reduced incidence of acute symptomatic seizures during 48 h post-SE, and a delayed time to spontaneous seizures onset compared to vehicle controls. Upon reparixin discontinuation, mice developed spontaneous seizures similar to vehicle mice, as shown by EEG monitoring at 14 days and 2.5 months post-SE. In the same epileptic mice, reparixin reduced neuronal cell loss in the hippocampus vs vehicle-injected mice, as assessed by Nissl staining at completion of EEG monitoring. Reparixin administration for 2 weeks in mice with established chronic seizures, reduced by 2-fold on average seizure number vs pre-treatment baseline, and this effect was reversible upon drug discontinuation. No significant changes in seizure number were measured in vehicle-injected epileptic mice that were EEG monitored in parallel. Data show that CXCL1-IL-8 signaling is activated in experimental and human epilepsy and contributes to acute and chronic seizures in mice, therefore representing a potential new target to attain anti-ictogenic effects.
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http://dx.doi.org/10.1016/j.nbd.2021.105468DOI Listing
October 2021

Seizure-mediated iron accumulation and dysregulated iron metabolism after status epilepticus and in temporal lobe epilepsy.

Acta Neuropathol 2021 10 22;142(4):729-759. Epub 2021 Jul 22.

Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.

Neuronal dysfunction due to iron accumulation in conjunction with reactive oxygen species (ROS) could represent an important, yet underappreciated, component of the epileptogenic process. However, to date, alterations in iron metabolism in the epileptogenic brain have not been addressed in detail. Iron-related neuropathology and antioxidant metabolic processes were investigated in resected brain tissue from patients with temporal lobe epilepsy and hippocampal sclerosis (TLE-HS), post-mortem brain tissue from patients who died after status epilepticus (SE) as well as brain tissue from the electrically induced SE rat model of TLE. Magnetic susceptibility of the presumed seizure-onset zone from three patients with focal epilepsy was compared during and after seizure activity. Finally, the cellular effects of iron overload were studied in vitro using an acute mouse hippocampal slice preparation and cultured human fetal astrocytes. While iron-accumulating neurons had a pyknotic morphology, astrocytes appeared to acquire iron-sequestrating capacity as indicated by prominent ferritin expression and iron retention in the hippocampus of patients with SE or TLE. Interictal to postictal comparison revealed increased magnetic susceptibility in the seizure-onset zone of epilepsy patients. Post-SE rats had consistently higher hippocampal iron levels during the acute and chronic phase (when spontaneous recurrent seizures are evident). In vitro, in acute slices that were exposed to iron, neurons readily took up iron, which was exacerbated by induced epileptiform activity. Human astrocyte cultures challenged with iron and ROS increased their antioxidant and iron-binding capacity, but simultaneously developed a pro-inflammatory phenotype upon chronic exposure. These data suggest that seizure-mediated, chronic neuronal iron uptake might play a role in neuronal dysfunction/loss in TLE-HS. On the other hand, astrocytes sequester iron, specifically in chronic epilepsy. This function might transform astrocytes into a highly resistant, pro-inflammatory phenotype potentially contributing to pro-epileptogenic inflammatory processes.
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http://dx.doi.org/10.1007/s00401-021-02348-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8423709PMC
October 2021

Toward a refined genotype-phenotype classification scheme for the international consensus classification of Focal Cortical Dysplasia.

Brain Pathol 2021 07;31(4):e12956

Epilepsy Center, Cleveland Clinic Foundation, Cleveland, OH, USA.

Focal Cortical Dysplasia (FCD) is the most common cause of drug-resistant focal epilepsy in children and young adults. The diagnosis of currently defined FCD subtypes relies on a histopathological assessment of surgical brain tissue. The many ongoing challenges in the diagnosis of FCD and their various subtypes mandate, however, continuous research and consensus agreement to develop a reliable classification scheme. Advanced neuroimaging and genetic studies have proven to augment the diagnosis of FCD subtypes and should be considered for an integrated clinico-pathological and molecular classification. In this review, we will discuss the histopathological foundation of the current FCD classification and potential advancements when using genetic analysis of somatic brain mutations in neurosurgically resected brain specimens and postprocessing of presurgical neuroimaging data. Combining clinical, imaging, histopathology, and molecular studies will help to define the disease spectrum better and finally unveil FCD-specific treatment options.
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http://dx.doi.org/10.1111/bpa.12956DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8412090PMC
July 2021

Impaired myelin production due to an intrinsic failure of oligodendrocytes in mTORpathies.

Neuropathol Appl Neurobiol 2021 10 26;47(6):812-825. Epub 2021 Jul 26.

Department of Pediatrics and Adolescent Medicine, Medical University of Vienna - Affiliated Partner of the ERN EpiCARE, Vienna, Austria.

Aims: We aim to evaluate if the myelin pathology observed in epilepsy-associated focal cortical dysplasia type 2B (FCD2B) and-histologically indistinguishable-cortical tubers of tuberous sclerosis complex (TSC) is primarily related to the underlying malformation or constitutes a secondary phenomenon due to the toxic microenvironment created by epileptic seizures. We also aim to investigate the possible beneficial effect of the mTOR pathway regulator everolimus on white matter pathology.

Methods: Primary mixed glial cell cultures derived from epilepsy surgery specimens of one TSC and seven FCD2B patients were grown on polycaprolactone fibre matrices and analysed using immunofluorescence and electron microscopy. Unaffected white matter from three age-matched epilepsy patients with mild malformations of cortical development (mMCD) and one with FCD3D served as controls. Additionally, TSC2 knock-out was performed using an oligodendroglial cell line. Myelination capacities of nanofibre grown cells in an inflammatory environment after mTOR-inhibitor treatment with everolimus were further investigated.

Results: Reduced oligodendroglial turnover, directly related to a lower myelin content was found in the patients' primary cells. In our culture model of myelination dynamics, primary cells grown under 'inflammatory condition' showed decreased myelination, that was repaired by treatment with everolimus.

Conclusions: Results obtained in patient-derived primary oligodendroglial and TSC2 knock-out cells suggest that maturation of oligodendroglia and production of a proper myelin sheath seem to be impaired as a result of mTOR pathway disturbance. Hence, oligodendroglial pathology may reflect a more direct effect of the abnormal genetic programme rather than to be an inactive bystander of chronic epilepsy.
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http://dx.doi.org/10.1111/nan.12744DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8518586PMC
October 2021

Interplay between immunity and amyotrophic lateral sclerosis: Clinical impact.

Neurosci Biobehav Rev 2021 08 19;127:958-978. Epub 2021 Jun 19.

Department of Neurology and ALS Centre, University of Piemonte Orientale, Maggiore Della Carità Hospital, Corso Mazzini 18, Novara, 28100, Italy. Electronic address:

Amyotrophic lateral sclerosis (ALS) is a debilitating and rapidly fatal neurodegenerative disease. Despite decades of research and many new insights into disease biology over the 150 years since the disease was first described, causative pathogenic mechanisms in ALS remain poorly understood, especially in sporadic cases. Our understanding of the role of the immune system in ALS pathophysiology, however, is rapidly expanding. The aim of this manuscript is to summarize the recent advances regarding the immune system involvement in ALS, with particular attention to clinical translation. We focus on the potential pathophysiologic mechanism of the immune system in ALS, discussing local and systemic factors (blood, cerebrospinal fluid, and microbiota) that influence ALS onset and progression in animal models and people. We also explore the potential of Positron Emission Tomography to detect neuroinflammation in vivo, and discuss ongoing clinical trials of therapies targeting the immune system. With validation in human patients, new evidence in this emerging field will serve to identify novel therapeutic targets and provide realistic hope for personalized treatment strategies.
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http://dx.doi.org/10.1016/j.neubiorev.2021.06.027DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8428677PMC
August 2021

Balloon cells promote immune system activation in focal cortical dysplasia type 2b.

Neuropathol Appl Neurobiol 2021 10 8;47(6):826-839. Epub 2021 Jun 8.

Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands.

Aims: Focal cortical dysplasia (FCD) type 2 is an epileptogenic malformation of the neocortex associated with somatic mutations in the mammalian target of rapamycin (mTOR) pathway. Histopathologically, FCD 2 is subdivided into FCD 2a and FCD 2b, the only discriminator being the presence of balloon cells (BCs) in FCD 2b. While pro-epileptogenic immune system activation and inflammatory responses are commonly detected in both subtypes, it is unknown what contextual role BCs play.

Methods: The present study employed RNA sequencing of surgically resected brain tissue from FCD 2a (n = 11) and FCD 2b (n = 20) patients compared to autopsy control (n = 9) focusing on three immune system processes: adaptive immunity, innate immunity and cytokine production. This analysis was followed by immunohistochemistry on a clinically well-characterised FCD 2 cohort.

Results: Differential expression analysis revealed stronger expression of components of innate immunity, adaptive immunity and cytokine production in FCD 2b than in FCD 2a, particularly complement activation and antigen presentation. Immunohistochemical analysis confirmed these findings, with strong expression of leukocyte antigen I and II in FCD 2b as compared to FCD 2a. Moreover, T-lymphocyte tissue infiltration was elevated in FCD 2b. Expression of markers of immune system activation in FCD 2b was concentrated in subcortical white matter. Lastly, antigen presentation was strongly correlated with BC load in FCD 2b lesions.

Conclusion: We conclude that, next to mutation-driven mTOR activation and seizure activity, BCs are crucial drivers of inflammation in FCD 2b. Our findings indicate that therapies targeting inflammation may be beneficial in FCD 2b.
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http://dx.doi.org/10.1111/nan.12736DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8518746PMC
October 2021

Pathomechanisms of ALS8: altered autophagy and defective RNA binding protein (RBP) homeostasis due to the VAPB P56S mutation.

Cell Death Dis 2021 05 10;12(5):466. Epub 2021 May 10.

Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany.

Mutations in RNA binding proteins (RBPs) and in genes regulating autophagy are frequent causes of familial amyotrophic lateral sclerosis (fALS). The P56S mutation in vesicle-associated membrane protein-associated protein B (VAPB) leads to fALS (ALS8) and spinal muscular atrophy (SMA). While VAPB is primarily involved in the unfolded protein response (UPR), vesicular trafficking and in initial steps of the autophagy pathway, the effect of mutant P56S-VAPB on autophagy regulation in connection with RBP homeostasis has not been explored yet. Examining the muscle biopsy of our index ALS8 patient of European origin revealed globular accumulations of VAPB aggregates co-localised with autophagy markers LC3 and p62 in partially atrophic and atrophic muscle fibres. In line with this skin fibroblasts obtained from the same patient showed accumulation of P56S-VAPB aggregates together with LC3 and p62. Detailed investigations of autophagic flux in cell culture models revealed that P56S-VAPB alters both initial and late steps of the autophagy pathway. Accordingly, electron microscopy complemented with live cell imaging highlighted the impaired fusion of accumulated autophagosomes with lysosomes in cells expressing P56S-VAPB. Consistent with these observations, neuropathological studies of brain and spinal cord of P56S-VAPB transgenic mice revealed signs of neurodegeneration associated with altered protein quality control and defective autophagy. Autophagy and RBP homeostasis are interdependent, as demonstrated by the cytoplasmic mis-localisation of several RBPs including pTDP-43, FUS, Matrin 3 which often sequestered with P56S-VAPB aggregates both in cell culture and in the muscle biopsy of the ALS8 patient. Further confirming the notion that aggregation of the RBPs proceeds through the stress granule (SG) pathway, we found persistent G3BP- and TIAR1-positive SGs in P56S-VAPB expressing cells as well as in the ALS8 patient muscle biopsy. We conclude that P56S-VAPB-ALS8 involves a cohesive pathomechanism of aberrant RBP homeostasis together with dysfunctional autophagy.
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http://dx.doi.org/10.1038/s41419-021-03710-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8110809PMC
May 2021

Toward a better definition of focal cortical dysplasia: An iterative histopathological and genetic agreement trial.

Epilepsia 2021 06 5;62(6):1416-1428. Epub 2021 May 5.

Department of Neuropathology, Institute of Neurology, University College London, London, UK.

Objective: Focal cortical dysplasia (FCD) is a major cause of difficult-to-treat epilepsy in children and young adults, and the diagnosis is currently based on microscopic review of surgical brain tissue using the International League Against Epilepsy classification scheme of 2011. We developed an iterative histopathological agreement trial with genetic testing to identify areas of diagnostic challenges in this widely used classification scheme.

Methods: Four web-based digital pathology trials were completed by 20 neuropathologists from 15 countries using a consecutive series of 196 surgical tissue blocks obtained from 22 epilepsy patients at a single center. Five independent genetic laboratories performed screening or validation sequencing of FCD-relevant genes in paired brain and blood samples from the same 22 epilepsy patients.

Results: Histopathology agreement based solely on hematoxylin and eosin stainings was low in Round 1, and gradually increased by adding a panel of immunostainings in Round 2 and the Delphi consensus method in Round 3. Interobserver agreement was good in Round 4 (kappa = .65), when the results of genetic tests were disclosed, namely, MTOR, AKT3, and SLC35A2 brain somatic mutations in five cases and germline mutations in DEPDC5 and NPRL3 in two cases.

Significance: The diagnoses of FCD 1 and 3 subtypes remained most challenging and were often difficult to differentiate from a normal homotypic or heterotypic cortical architecture. Immunohistochemistry was helpful, however, to confirm the diagnosis of FCD or no lesion. We observed a genotype-phenotype association for brain somatic mutations in SLC35A2 in two cases with mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy. Our results suggest that the current FCD classification should recognize a panel of immunohistochemical stainings for a better histopathological workup and definition of FCD subtypes. We also propose adding the level of genetic findings to obtain a comprehensive, reliable, and integrative genotype-phenotype diagnosis in the near future.
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http://dx.doi.org/10.1111/epi.16899DOI Listing
June 2021

MicroRNA-34a activation in tuberous sclerosis complex during early brain development may lead to impaired corticogenesis.

Neuropathol Appl Neurobiol 2021 10 14;47(6):796-811. Epub 2021 Jun 14.

Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands.

Aims: Tuberous sclerosis complex (TSC) is a genetic disorder associated with dysregulation of the mechanistic target of rapamycin complex 1 (mTORC1) signalling pathway. Neurodevelopmental disorders, frequently present in TSC, are linked to cortical tubers in the brain. We previously reported microRNA-34a (miR-34a) among the most upregulated miRs in tubers. Here, we characterised miR-34a expression in tubers with the focus on the early brain development and assessed the regulation of mTORC1 pathway and corticogenesis by miR-34a.

Methods: We analysed the expression of miR-34a in resected cortical tubers (n = 37) compared with autopsy-derived control tissue (n = 27). The effect of miR-34a overexpression on corticogenesis was assessed in mice at E18. The regulation of the mTORC1 pathway and the expression of the bioinformatically predicted target genes were assessed in primary astrocyte cultures from three patients with TSC and in SH-SY5Y cells following miR-34a transfection.

Results: The peak of miR-34a overexpression in tubers was observed during infancy, concomitant with the presence of pathological markers, particularly in giant cells and dysmorphic neurons. miR-34a was also strongly expressed in foetal TSC cortex. Overexpression of miR-34a in mouse embryos decreased the percentage of cells migrated to the cortical plate. The transfection of miR-34a mimic in TSC astrocytes negatively regulated mTORC1 and decreased the expression of the target genes RAS related (RRAS) and NOTCH1.

Conclusions: MicroRNA-34a is most highly overexpressed in tubers during foetal and early postnatal brain development. miR-34a can negatively regulate mTORC1; however, it may also contribute to abnormal corticogenesis in TSC.
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http://dx.doi.org/10.1111/nan.12717DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8519131PMC
October 2021

Proteomics and Transcriptomics of the Hippocampus and Cortex in SUDEP and High-Risk SUDEP Patients.

Neurology 2021 05 28;96(21):e2639-e2652. Epub 2021 Apr 28.

From the Comprehensive Epilepsy Center (D.F.L., C.V., S.D., D.F., O.D.), Proteomics Laboratory (E.K., S.N., B.U.), Division of Advanced Research Technologies, and Department of Biochemistry and Molecular Pharmacology (B.U.), NYU School of Medicine; Department of Neurology (D.F.L., G.P., A.F., E.D., S.D., D.F., T.W., B.U., O.D.), Center for Cognitive Neurology (G.P., A.F., E.D., T.W.), Department of Pathology (T.W.), and Department of Psychiatry (T.W.), NYU Langone Health and School of Medicine, New York; Department of (Neuro)Pathology (J.D.M., J.J.A., E.A.v.V., E.A.), Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, the Netherlands; Alzheimer's and Prion Diseases Team (G.P.), Paris Brain Institute, CNRS, UMR 7225, INSERM 1127, Sorbonne University UM75, Paris, France; Brain & Mind Centre and School of Medical Sciences (E.D.), Faculty of Medicine and Health, University of Sydney, Australia; Biomedical Hosting LLC (M.A.), Arlington, MA; School of Biotechnology and Biomolecular Sciences (B.J.C., M.J.), University of New South Wales, Sydney, Australia; Amsterdam UMC (J.C.B., S.I.), Vrije Universiteit Amsterdam, Department of Neurosurgery, Amsterdam Neuroscience, De Boelelaan 1117; Swammerdam Institute for Life Sciences (E.A.v.V.), Center for Neuroscience, University of Amsterdam, the Netherlands; Department of Clinical and Experimental Epilepsy (B.D., C.S., M.T.), University College London Institute of Neurology, UK; and Stichting Epilepsie Instellingen Nederland (R.T., E.A.), Heemstede, the Netherlands

Objective: To identify the molecular signaling pathways underlying sudden unexpected death in epilepsy (SUDEP) and high-risk SUDEP compared to control patients with epilepsy.

Methods: For proteomics analyses, we evaluated the hippocampus and frontal cortex from microdissected postmortem brain tissue of 12 patients with SUDEP and 14 with non-SUDEP epilepsy. For transcriptomics analyses, we evaluated hippocampus and temporal cortex surgical brain tissue from patients with mesial temporal lobe epilepsy: 6 low-risk and 8 high-risk SUDEP as determined by a short (<50 seconds) or prolonged (≥50 seconds) postictal generalized EEG suppression (PGES) that may indicate severely depressed brain activity impairing respiration, arousal, and protective reflexes.

Results: In autopsy hippocampus and cortex, we observed no proteomic differences between patients with SUDEP and those with non-SUDEP epilepsy, contrasting with our previously reported robust differences between epilepsy and controls without epilepsy. Transcriptomics in hippocampus and cortex from patients with surgical epilepsy segregated by PGES identified 55 differentially expressed genes (37 protein-coding, 15 long noncoding RNAs, 3 pending) in hippocampus.

Conclusion: The SUDEP proteome and high-risk SUDEP transcriptome were similar to those in other patients with epilepsy in hippocampus and cortex, consistent with diverse epilepsy syndromes and comorbid conditions associated with SUDEP. Studies with larger cohorts and different epilepsy syndromes, as well as additional anatomic regions, may identify molecular mechanisms of SUDEP.
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http://dx.doi.org/10.1212/WNL.0000000000011999DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8205452PMC
May 2021

A serum microRNA sequence reveals fragile X protein pathology in amyotrophic lateral sclerosis.

Brain 2021 05;144(4):1214-1229

Department of Neurology, Ulm University, Ulm, Germany.

Knowledge about converging disease mechanisms in the heterogeneous syndrome amyotrophic lateral sclerosis (ALS) is rare, but may lead to therapies effective in most ALS cases. Previously, we identified serum microRNAs downregulated in familial ALS, the majority of sporadic ALS patients, but also in presymptomatic mutation carriers. A 5-nucleotide sequence motif (GDCGG; D = G, A or U) was strongly enriched in these ALS-related microRNAs. We hypothesized that deregulation of protein(s) binding predominantly to this consensus motif was responsible for the ALS-linked microRNA fingerprint. Using microRNA pull-down assays combined with mass spectrometry followed by extensive biochemical validation, all members of the fragile X protein family, FMR1, FXR1 and FXR2, were identified to directly and predominantly interact with GDCGG microRNAs through their structurally disordered RGG/RG domains. Preferential association of this protein family with ALS-related microRNAs was confirmed by in vitro binding studies on a transcriptome-wide scale. Immunohistochemistry of lumbar spinal cord revealed aberrant expression level and aggregation of FXR1 and FXR2 in C9orf72- and FUS-linked familial ALS, but also patients with sporadic ALS. Further analysis of ALS autopsies and induced pluripotent stem cell-derived motor neurons with FUS mutations showed co-aggregation of FXR1 with FUS. Hence, our translational approach was able to take advantage of blood microRNAs to reveal CNS pathology, and suggests an involvement of the fragile X-related proteins in familial and sporadic ALS already at a presymptomatic stage. The findings may uncover disease mechanisms relevant to many patients with ALS. They furthermore underscore the systemic, extra-CNS aspect of ALS.
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http://dx.doi.org/10.1093/brain/awab018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8105042PMC
May 2021

Altered perivascular fibroblast activity precedes ALS disease onset.

Nat Med 2021 04 15;27(4):640-646. Epub 2021 Apr 15.

University of Ulm, Neurology Clinic, Ulm, Germany.

Apart from well-defined factors in neuronal cells, only a few reports consider that the variability of sporadic amyotrophic lateral sclerosis (ALS) progression can depend on less-defined contributions from glia and blood vessels. In this study we use an expression-weighted cell-type enrichment method to infer cell activity in spinal cord samples from patients with sporadic ALS and mouse models of this disease. Here we report that patients with sporadic ALS present cell activity patterns consistent with two mouse models in which enrichments of vascular cell genes preceded microglial response. Notably, during the presymptomatic stage, perivascular fibroblast cells showed the strongest gene enrichments, and their marker proteins SPP1 and COL6A1 accumulated in enlarged perivascular spaces in patients with sporadic ALS. Moreover, in plasma of 574 patients with ALS from four independent cohorts, increased levels of SPP1 at disease diagnosis repeatedly predicted shorter survival with stronger effect than the established risk factors of bulbar onset or neurofilament levels in cerebrospinal fluid. We propose that the activity of the recently discovered perivascular fibroblast can predict survival of patients with ALS and provide a new conceptual framework to re-evaluate definitions of ALS etiology.
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http://dx.doi.org/10.1038/s41591-021-01295-9DOI Listing
April 2021

Biallelic variants in LIG3 cause a novel mitochondrial neurogastrointestinal encephalomyopathy.

Brain 2021 06;144(5):1451-1466

Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, 611-0011, Japan.

Abnormal gut motility is a feature of several mitochondrial encephalomyopathies, and mutations in genes such as TYMP and POLG, have been linked to these rare diseases. The human genome encodes three DNA ligases, of which only one, ligase III (LIG3), has a mitochondrial splice variant and is crucial for mitochondrial health. We investigated the effect of reduced LIG3 activity and resulting mitochondrial dysfunction in seven patients from three independent families, who showed the common occurrence of gut dysmotility and neurological manifestations reminiscent of mitochondrial neurogastrointestinal encephalomyopathy. DNA from these patients was subjected to whole exome sequencing. In all patients, compound heterozygous variants in a new disease gene, LIG3, were identified. All variants were predicted to have a damaging effect on the protein. The LIG3 gene encodes the only mitochondrial DNA (mtDNA) ligase and therefore plays a pivotal role in mtDNA repair and replication. In vitro assays in patient-derived cells showed a decrease in LIG3 protein levels and ligase activity. We demonstrated that the LIG3 gene defects affect mtDNA maintenance, leading to mtDNA depletion without the accumulation of multiple deletions as observed in other mitochondrial disorders. This mitochondrial dysfunction is likely to cause the phenotypes observed in these patients. The most prominent and consistent clinical signs were severe gut dysmotility and neurological abnormalities, including leukoencephalopathy, epilepsy, migraine, stroke-like episodes, and neurogenic bladder. A decrease in the number of myenteric neurons, and increased fibrosis and elastin levels were the most prominent changes in the gut. Cytochrome c oxidase (COX) deficient fibres in skeletal muscle were also observed. Disruption of lig3 in zebrafish reproduced the brain alterations and impaired gut transit in vivo. In conclusion, we identified variants in the LIG3 gene that result in a mitochondrial disease characterized by predominant gut dysmotility, encephalopathy, and neuromuscular abnormalities.
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http://dx.doi.org/10.1093/brain/awab056DOI Listing
June 2021

Dissecting the Molecular Determinants of GABA Receptors Current Rundown, a Hallmark of Refractory Human Epilepsy.

Brain Sci 2021 Mar 30;11(4). Epub 2021 Mar 30.

Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, 00185 Rome, Italy.

GABA receptors-(Rs) are fundamental for the maintenance of an efficient inhibitory function in the central nervous system (CNS). Their dysfunction is associated with a wide range of CNS disorders, many of which characterized by seizures and epilepsy. Recently, an increased use-dependent desensitization due to a repetitive GABA stimulation (GABA current rundown) of GABARs has been associated with drug-resistant temporal lobe epilepsy (TLE). Here, we aimed to investigate the molecular determinants of GABA current rundown with two different heterologous expression systems ( oocytes and human embryonic kidney cells; HEK) which allowed us to manipulate receptor stoichiometry and to study the GABA current rundown on different GABAR configurations. To this purpose, we performed electrophysiology experiments using two-electrode voltage clamp in oocytes and confirming part of our results in HEK. We found that different degrees of GABA current rundown can be associated with the expression of different GABAR β-subunits reaching the maximum current decrease when functional α1β2 receptors are expressed. Furthermore, the blockade of phosphatases can prevent the current rundown observed in α1β2 GABARs. Since GABAR represents one important therapeutic target in the treatment of human epilepsy, our results could open new perspectives on the therapeutic management of drug-resistant patients showing a GABAergic impairment.
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http://dx.doi.org/10.3390/brainsci11040441DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8066365PMC
March 2021

Upregulation of the pathogenic transcription factor SPI1/PU.1 in tuberous sclerosis complex and focal cortical dysplasia by oxidative stress.

Brain Pathol 2021 09 30;31(5):e12949. Epub 2021 Mar 30.

Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.

Tuberous sclerosis complex (TSC) is a congenital disorder characterized by cortical malformations and concomitant epilepsy caused by loss-of-function mutations in the mTOR suppressors TSC1 or TSC2. While the underlying molecular changes caused by mTOR activation in TSC have previously been investigated, the drivers of these transcriptional change have not been fully elucidated. A better understanding of the perturbed transcriptional regulation could lead to the identification of novel pathways for therapeutic intervention not only in TSC, but other genetic epilepsies in which mTOR activation plays a key role, such as focal cortical dysplasia 2b (FCD). Here, we analyzed RNA sequencing data from cortical tubers and a tsc2 zebrafish. We identified differential expression of the transcription factors (TFs) SPI1/PU.1, IRF8, GBX2, and IKZF1 of which SPI1/PU.1 and IRF8 targets were enriched among the differentially expressed genes. Furthermore, for SPI1/PU.1 these findings were conserved in TSC zebrafish model. Next, we confirmed overexpression of SPI1/PU.1 on the RNA and protein level in a separate cohort of surgically resected TSC tubers and FCD tissue, in fetal TSC tissue, and a Tsc1 mouse model of TSC. Subsequently, we validated the expression of SPI1/PU.1 in dysmorphic cells with mTOR activation in TSC tubers. In fetal TSC, we detected SPI1/PU.1 expression prenatally and elevated RNA Spi1 expression in Tsc1 mice before the development of seizures. Finally, in vitro, we identified that in astrocytes and neurons SPI1 transcription was driven by H O -induced oxidative stress, independent of mTOR. We identified SPI1/PU.1 as a novel TF involved in the pro-inflammatory gene expression of malformed cells in TSC and FCD 2b. This transcriptional program is activated in response to oxidative stress and already present prenatally. Importantly, SPI1/PU.1 protein appears to be strictly limited to malformed cells, as we did not find SPI1/PU.1 protein expression in mice nor in our in vitro models.
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http://dx.doi.org/10.1111/bpa.12949DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8412124PMC
September 2021

Expression and Cell Type-specific Localization of Inflammasome Sensors in the Spinal Cord of SOD1 Mice and Sporadic Amyotrophic lateral sclerosis Patients.

Neuroscience 2021 05 26;463:288-302. Epub 2021 Mar 26.

Institute of Neuroanatomy, RWTH Aachen University, Wendlingweg 2, Aachen, Germany; Center of Experimental Medicine, Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, Martinistraße 52, Hamburg, Germany. Electronic address:

Inflammasomes are key components of the innate immune system and activation of these multiprotein platforms is a crucial event in the etiopathology of amyotrophic lateral sclerosis (ALS). Inflammasomes consist of a pattern recognition receptor (PRR), the adaptor protein apoptosis-associated speck-like protein containing a CARD (ASC) and caspase 1. Exogenous or endogenous "danger signals" can trigger inflammasome assembly and promote maturation and release of pro-inflammatory cytokines, including interleukin 1β. Previous studies have demonstrated presence and activation of NLRP3 in spinal cord tissue from SOD1 mice and human sporadic ALS (sALS) patients. However, regulation and cell type-specific localization of other well-known PRRs has not yet been analysed in ALS. Here, we explored gene expression, protein concentration and cell type-specific localization of the NLRP1, NLRC4 and AIM2 inflammasomes in spinal cord samples from SOD1 mice and sALS patients. Transcription levels of NLRP1 and NLRC4, but not AIM2, were elevated in symptomatic SOD1 animals. Immunoblotting revealed elevated protein levels of NLRC4, which were significantly increased in sALS vs. control patients. Immunofluorescence studies revealed neuronal labelling of all investigated PRRs. Staining of AIM2 was detected in all types of glia, whereas glial type-specific labelling was observed for NLRP1 and NLRC4. Our findings revealed pathology-related and cell type-specific differences in the expression of subsets of PRRs. Besides NLRP3, NLRC4 appears to be linked more closely to ALS pathogenesis.
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http://dx.doi.org/10.1016/j.neuroscience.2021.03.023DOI Listing
May 2021

Early epileptiform EEG activity in infants with tuberous sclerosis complex predicts epilepsy and neurodevelopmental outcomes.

Epilepsia 2021 05 29;62(5):1208-1219. Epub 2021 Mar 29.

Department of Development and Regeneration, Section Pediatric Neurology, Catholic University of Leuven (KU Leuven), Leuven, Belgium.

Objective: To study the association between timing and characteristics of the first electroencephalography (EEG) with epileptiform discharges (ED-EEG) and epilepsy and neurodevelopment at 24 months in infants with tuberous sclerosis complex (TSC).

Methods: Patients enrolled in the prospective Epileptogenesis in a genetic model of epilepsy - Tuberous sclerosis complex (EPISTOP) trial, had serial EEG monitoring until the age of 24 months. The timing and characteristics of the first ED-EEG were studied in relation to clinical outcome. Epilepsy-related outcomes were analyzed separately in a conventionally followed group (initiation of vigabatrin after seizure onset) and a preventive group (initiation of vigabatrin before seizures, but after appearance of interictal epileptiform discharges [IEDs]).

Results: Eighty-three infants with TSC were enrolled at a median age of 28 days (interquartile range [IQR] 14-54). Seventy-nine of 83 patients (95%) developed epileptiform discharges at a median age of 77 days (IQR 23-111). Patients with a pathogenic TSC2 variant were significantly younger (P-value .009) at first ED-EEG and more frequently had multifocal IED (P-value .042) than patients with a pathogenic TSC1 variant. A younger age at first ED-EEG was significantly associated with lower cognitive (P-value .010), language (P-value .001), and motor (P-value .013) developmental quotients at 24 months. In the conventional group, 48 of 60 developed seizures. In this group, the presence of focal slowing on the first ED-EEG was predictive of earlier seizure onset (P-value .030). Earlier recording of epileptiform discharges (P-value .019), especially when multifocal (P-value .026) was associated with higher risk of drug-resistant epilepsy. In the preventive group, timing, distribution of IED, or focal slowing, was not associated with the epilepsy outcomes. However, when multifocal IEDs were present on the first ED-EEG, preventive treatment delayed the onset of seizures significantly (P-value <.001).

Significance: Early EEG findings help to identify TSC infants at risk of severe epilepsy and neurodevelopmental delay and those who may benefit from preventive treatment with vigabatrin.
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http://dx.doi.org/10.1111/epi.16892DOI Listing
May 2021

Hsp90-mediated regulation of DYRK3 couples stress granule disassembly and growth via mTORC1 signaling.

EMBO Rep 2021 05 19;22(5):e51740. Epub 2021 Mar 19.

Department of Biomedical, Metabolic and Neural Sciences, Centre for Neuroscience and Nanotechnology, University of Modena and Reggio Emilia, Modena, Italy.

Stress granules (SGs) are dynamic condensates associated with protein misfolding diseases. They sequester stalled mRNAs and signaling factors, such as the mTORC1 subunit raptor, suggesting that SGs coordinate cell growth during and after stress. However, the molecular mechanisms linking SG dynamics and signaling remain undefined. We report that the chaperone Hsp90 is required for SG dissolution. Hsp90 binds and stabilizes the dual-specificity tyrosine-phosphorylation-regulated kinase 3 (DYRK3) in the cytosol. Upon Hsp90 inhibition, DYRK3 dissociates from Hsp90 and becomes inactive. Inactive DYRK3 is subjected to two different fates: it either partitions into SGs, where it is protected from irreversible aggregation, or it is degraded. In the presence of Hsp90, DYRK3 is active and promotes SG disassembly, restoring mTORC1 signaling and translation. Thus, Hsp90 links stress adaptation and cell growth by regulating the activity of a key kinase involved in condensate disassembly and translation restoration.
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http://dx.doi.org/10.15252/embr.202051740DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8097338PMC
May 2021

Angiocentric glioma-associated seizures: The possible role of EATT2, pyruvate carboxylase and glutamine synthetase.

Seizure 2021 Mar 16;86:152-154. Epub 2021 Feb 16.

Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Italy.

Purpose: Our purpose was to better understand the pathogenesis of seizures associated with angiocentric glioma. Angiocentric glioma is an indolent and rare low-grade glioma. Its typical clinical presentation is with epileptic seizures. The pathogenesis of tumor-associated seizures is poorly understood. Among the possible pathomechanisms, the increased neurotoxic concentrations of the glutamate has been proposed. Glutamate transporters, pyruvate carboxylase and glutamine synthetase are involved in maintaining the physiological concentration of glutamate in the inter synaptic spaces.

Methods: We evaluated the immunohistochemical expression of EAAT2 (the most important glutamate transporter), pyruvate carboxylase and glutamine synthetase in 17 angiocentric gliomas.

Results: EAAT2 was never expressed (0%) in the neoplastic cells in none of the cases studied. Pyruvate carboxylase was expressed in the cytoplasm of the neoplastic cells in 16/17 cases (94 %). Glutamine synthetase was expressed in the cytoplasm of the neoplastic cells in 15/17 cases (88 %).

Conclusion: The net result of this enzymatic expression, in particular considering the loss of EAAT2, could be an increased glutamate concentration in the synaptic clef, which might increase local network excitability initially involving intratumoral neurons. The observation that the angiocentric glioma-associated epilepsy might be at least in part related to EAAT2 deficiency opens up interesting therapeutic perspectives.
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http://dx.doi.org/10.1016/j.seizure.2021.02.014DOI Listing
March 2021

Can we use intraoperative high-frequency oscillations to guide tumor-related epilepsy surgery?

Epilepsia 2021 04 22;62(4):997-1004. Epub 2021 Feb 22.

Department of Neurology and Neurosurgery, University Medical Center Utrecht Brain Center, Utrecht, the Netherlands.

Objective: In people with low-grade intrinsic brain tumors, an epileptic focus is often located close to the lesion. High-frequency oscillations (HFOs) in electrocorticography (ECoG) might help to delineate this focus. We investigated the relationship between HFOs and low-grade brain tumors and their potential value for tumor-related epilepsy surgery.

Methods: We analyzed pre- and postresection intraoperative ECoG in 41 patients with refractory epilepsy and a low-grade lesion. Electrodes were designated as overlying the tumor, adjacent resected tissue (peritumoral), or outside the resection bed using magnetic resonance imaging (MRI) and intraoperative photographs. We then used a semiautomated approach to detect HFOs as either ripples (80-250 Hz) or fast ripples (250-500 Hz).

Results: The rate of fast ripples was higher in electrodes covering tumor and peritumoral tissue than outside the resection (p = .04). Mesiotemporal tumors showed more ripples (p = .002), but not more fast ripples (p = .07), than superficial tumors. Rates of fast ripples were higher in glioma and extraventricular neurocytoma than in ganglioglioma or dysembryoplastic neuroepithelial tumor (DNET). The rate of ripples and fast ripples in postresection ECoG was not higher in patients with residual tumor tissue on MRI than those without. The rate of ripples in postresection ECoG was higher in patients with good than bad seizure outcome (p = .03). Fast ripples outside the resection and in post-ECoG seem related to seizure recurrence.

Significance: Fast ripples in intraoperative ECoG can be used to help guide resection in tumor-related epilepsy surgery. Preresection fast ripples occur predominantly in epileptogenic tumor and peritumoral tissue. Fast ripple rates are higher in glioma and extraventricular neurocytoma than in ganglioglioma and DNET.
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http://dx.doi.org/10.1111/epi.16845DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8248094PMC
April 2021

Human brain pathology in myotonic dystrophy type 1: A systematic review.

Neuropathology 2021 Feb;41(1):3-20

Medical Imaging, Anatomy, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, the Netherlands.

Brain involvement in myotonic dystrophy type 1 (DM1) is characterized by heterogeneous cognitive, behavioral, and affective symptoms and imaging alterations indicative of widespread grey and white matter involvement. The aim of the present study was to systematically review the literature on brain pathology in DM1. We conducted a structured search in EMBASE (index period 1974-2017) and MEDLINE (index period 1887-2017) on December 11, 2017, using free text and index search terms related to myotonic dystrophy type 1 and brain structures or regions. Eligible studies were full-text studies reporting on microscopic brain pathology of DM1 patients without potentially interfering comorbidity. We discussed the findings based on the anatomical region and the nature of the anomaly. Neuropathological findings in DM1 can be classified as follows: (1) protein and nucleotide deposits; (2) changes in neurons and glial cells; and (3) white matter alterations. Most findings are unspecific to DM1 and may occur with physiological aging, albeit to a lesser degree. There are similarities and contrasts with Alzheimer's disease; both show the appearance of neurofibrillary tangles in the limbic system without plaque occurrence. Likewise, there is myelin loss and gliosis, and there are dilated perivascular spaces in the white matter resemblant of cerebral small vessel disease. However, we did not find evidence of lacunar infarction or microbleeding. The various neuropathological findings in DM1 are reflective of the heterogeneous clinical and neuroimaging features of the disease. The strength of conclusions from this study's findings is bounded by limited numbers of participants in studies, methodological constraints, and lack of assessed associations between histopathology and clinical or neuroimaging findings.
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http://dx.doi.org/10.1111/neup.12721DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7986875PMC
February 2021

Immunohistochemical Detection of Neural Stem Cells and Glioblastoma Stem Cells in the Subventricular Zone of Glioblastoma Patients.

J Histochem Cytochem 2021 05 17;69(5):349-364. Epub 2021 Feb 17.

Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia, Cancer Center Amsterdam, Amsterdam UMC at the Academic Medical Center, Amsterdam, The Netherlands.

Glioblastoma usually recurs after therapy consisting of surgery, radiotherapy, and chemotherapy. Recurrence is at least partly caused by glioblastoma stem cells (GSCs) that are maintained in intratumoral hypoxic peri-arteriolar microenvironments, or niches, in a slowly dividing state that renders GSCs resistant to radiotherapy and chemotherapy. Because the subventricular zone (SVZ) is a major niche for neural stem cells (NSCs) in the brain, we investigated whether GSCs are present in the SVZ at distance from the glioblastoma tumor. We characterized the SVZ of brains of seven glioblastoma patients using fluorescence immunohistochemistry and image analysis. NSCs were identified by CD133 and SOX2 but not CD9 expression, whereas GSCs were positive for all three biomarkers. NSCs were present in all seven samples and GSCs in six out of seven samples. The SVZ in all samples were hypoxic and expressed the same relevant chemokines and their receptors as GSC niches in glioblastoma tumors: stromal-derived factor-1α (SDF-1α), C-X-C receptor type 4 (CXCR4), osteopontin, and CD44. In conclusion, in glioblastoma patients, GSCs are present at distance from the glioblastoma tumor in the SVZ. These findings suggest that GSCs in the SVZ niche are protected against radiotherapy and chemotherapy and protected against surgical resection due to their distant localization and thus may contribute to tumor recurrence after therapy.
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http://dx.doi.org/10.1369/0022155421994679DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8091546PMC
May 2021

Neurite Outgrowth Inhibitor (NogoA) Is Upregulated in White Matter Lesions of Complex Cortical Malformations.

J Neuropathol Exp Neurol 2021 Feb;80(3):274-282

From the Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.

Complex cortical malformations (CCMs), such as hemimegalencephaly and polymicrogyria, are associated with drug-resistant epilepsy and developmental impairment. They share certain neuropathological characteristics including mammalian target of rapamycin (mTOR) activation and an atypical number of white matter neurons. To get a better understanding of the pathobiology of the lesion architecture, we investigated the role of neurite outgrowth inhibitor A (NogoA), a known regulator of neuronal migration. Epilepsy surgery specimens from 16 CCM patients were analyzed and compared with sections of focal cortical dysplasia IIB (FCD IIB, n = 22), tuberous sclerosis complex (TSC, n = 8) as well as healthy controls (n = 15). Immunohistochemistry was used to characterize NogoA, myelination, and mTOR signaling. Digital slides were evaluated automatically with ImageJ. NogoA staining showed a significantly higher expression within the white matter of CCM and FCD IIB, whereas cortical tubers presented levels similar to controls. Further analysis of possible associations of NogoA with other factors revealed a positive correlation with mTOR and seizure frequency. To identify the main expressing NogoA cell type, double staining revealed dysmorphic neuronal white matter cells. Increased NogoA expression is associated with profound inhibition of neuritic sprouting and therefore contributes to a decrease in neuronal network complexity in CCM patients.
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http://dx.doi.org/10.1093/jnen/nlaa159DOI Listing
February 2021

A Selective Competitive Inhibitor of Aldehyde Dehydrogenase 1A3 Hinders Cancer Cell Growth, Invasiveness and Stemness In Vitro.

Cancers (Basel) 2021 Jan 19;13(2). Epub 2021 Jan 19.

Department of Pharmaceutical Sciences, University of Piemonte Orientale, A. Avogadro, 28100 Novara, Italy.

Aldehyde dehydrogenase 1A3 (ALDH1A3) belongs to an enzymatic superfamily composed by 19 different isoforms, with a scavenger role, involved in the oxidation of a plethora of aldehydes to the respective carboxylic acids, through a NAD+-dependent reaction. Previous clinical studies highlighted the high expression of ALDH1A3 in cancer stem cells (CSCs) correlated to a higher risk of cancer relapses, chemoresistance and a poor clinical outcome. We report on the structural, biochemical, and cellular characterization of NR6, a new selective ALDH1A3 inhibitor derived from an already published ALDH non-selective inhibitor with cytotoxic activity on glioblastoma and colorectal cancer cells. Crystal structure, through X-Ray analysis, showed that NR6 binds a non-conserved tyrosine residue of ALDH1A3 which drives the selectivity towards this isoform, as supported by computational binding simulations. Moreover, NR6 shows anti-metastatic activity in wound healing and invasion assays and induces the downregulation of cancer stem cell markers. Overall, our work confirms the role of ALDH1A3 as an important target in glioblastoma and colorectal cells and propose NR6 as a promising molecule for future preclinical studies.
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http://dx.doi.org/10.3390/cancers13020356DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7835878PMC
January 2021
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